Shiba Ryoma (Hama Shogo), a genius lawyer, is the youngest co-partner at a major law firm. He is valued as a legal advisor to numerous major clients as he never loses a trial. His problem is that he can't find a proper assistant. After firing 99 of them, he's looking for no. 100, anmd that's when he meets Haruto (Hyodo Katsumi), a mysterious young man, and obviously a thug. As Haruto has a talent of pretendeing to be someone else, and as he knows his way of gathering secret information Haruto accepts Shiba as his new asstistant. Shiba invited Haruto to his home and is amazed as Haruto is able to speak to his plants, which so far only Shiba could. Although Shiba is considerably older than Haruto, is in completely inexperienced with respect to romance and lobe. He falls for the young man's charm, although he is too shy to accept his feelings for a long time. It's almost too late when he finally does, but then Haruto's real identity is revealed, which helps Shiba to win his most important case. Like many Japanese BL series, ”Love is a Poison” employs an ”opposites attract” plot, but as far as I know it's the first time that it comes in the shape of a justice drama. The combination of an unusual love story and an exciting legal case works surprisingly well, thanks to a good script and convincing actors.